In conjunction with data transfer there is often a need to bundle two or more data links to constitute a link aggregation group “LAG”. In many cases, one or more management processes need to be directed to a data stream that is a part of data traffic that is transmitted via a link aggregation group having egress ports in multiple functional entities of a network element. The data traffic may consist of data frames that can be for example Internet Protocol “IP” packets, Ethernet frames, or some other data entities. The network element can be for example an Internet Protocol “IP” router, a MultiProtocol Label Switching “MPLS” switch, a packet optical switch, an Ethernet switch, and/or a software-defined networking “SDN” controlled network element. The above-mentioned functional entities can be for example line cards or other entities of the network element which comprise the egress ports.
The management processes may comprise for example shaping for controlling the temporal rate profile of the data stream under consideration, i.e. to control the transmission rate and/or bursts of the data stream. For another example, the management processes may comprise deep packet inspection “DPI” for monitoring the content of the data stream. Furthermore, the management processes may comprise intrusion detection for monitoring the integrity of the data stream, e.g. for detecting a situation where unwanted data frames have been included into the data stream by an unauthorized malicious party.
The above-mentioned shaping, for example, can be configured on per Virtual Local Access Network “LAN” level or per MPLS Label Switched Path “LSP” level, and it may happen that a data stream to be shaped and representing a VLAN or a LSP is transmitted via egress ports located in multiple line cards or other functional entities comprising the egress ports. Traditionally, shapers are implemented in functional entities comprising the egress ports and this means that the desired shaping rate can be exceeded if the shaping in each functional entity works independently of the shaping in the other functional entities. For example, if four functional entities are used for transmitting a data stream to be shaped to be at most 100 Mbps and the shaping rate is set to be 100 Mbps in each of these four functional entities, the sum of the transmission rates of these functional entities can be up to 400 Mbps which is four times too much. On the other hand, if the shaping rate is set to be 25 Mbps in each of these four functional entities, the shaping is too restrictive during time periods when the whole data stream happens to flow via only one, two, or three of the four functional entities.
One approach for solving the above-described technical problem is such that shapers and/or other management devices located in multiple functional entities such as line cards are configured to communicate with each other so that the aggregate of the sub-streams sent via different ones of the functional entities is treated in an appropriate way. A challenge related to this approach is that data exchange between the shapers and/or other management devices located in the different ones of the functional entities would require a big amount of short-delay data traffic between these functional entities. In many cases it is not feasible, or not even possible, to arrange such data exchange between the functional entities. Another approach for solving the above-described technical problem is to carry out the shaping and/or other management processes in a place where the whole data stream under consideration is present. This place can be for example a switch fabric which distributes the data stream to the functional entities. This approach is however problematic with multicast “MC” traffic. Furthermore, in cases where there are many switch fabrics for load balancing, we have the problem that the switch fabrics should be configured to communicate with each other at a high rate and with a small delay.